Dynamo-electric machine.



f A. B. HBLD; DYNMO ELECTRIC MACHINE.

APPLICATION FILED MLY 13, 1907.

MMI

EH Hi UNITED sTA'rEs PATENT OFFICE.

ALAN B. FIELD, OF NORWOOD, OHIO, ASSIG NOR TO ALLIS-GHALMERS OOMPANYACOR- PORATION OF N JERSEY, AND THE BULLOOI ELECTRIC MNUFACTURINGCOMPANY,

A CORPORATION OF OHIO. I

DYNAMo-ELECTRIC MACHINE.

To all whom it, may concem:

Be rit known that I, ALAN BFILD, a sube ject of the King of England,`vresidi'ng at Norwood, in the county of Hamilton and State of Ohio, haveinvented certain' new'tand usef ful Improvements inIynamoEleetricMachines, of which the following' isfal full, clear, and exactspecification. My invention relates to means for reventinvlinting indynamo-electric mac es.

en electric generators are driven' by 1111-' steady sources of power, orwhen' synchronous motors are connected tol fluctuatingleads, there is atendencyi for the machines to rotate at a non-uniform speed. f Thehunting or. periodio-forward and backward vdial- 4 placement from a truesynchronous speed is often progressive and produces 'many und'e' hasbeen proposeclr to mount on the'outer extrem'ities of the ;fieldpole-pieces of,- the ma .chine andon opposite sides thereoftwoconducting'rings extending entirely around the machine, and to connectthese rings electricvao n flux, and thereby i these opposing currentsshall be low.

ally'by rods of conducting material which pass' through' thepole-pieces. Upon any. tendency to hunt there is anv accompanyingtendency-to Variation in vthe cross -m'agnetizflux of the machine, whichtends to set up currents in said rings androdsin opposition to thevariations in said cross' magnetizing to Vprevent the hunting. To obtainthe mostv satisfactory results'it is ess'ential thatthe resistance vofthe patls of renrally heretofore, however, in the' structures embodyingthe above feature the connections between 'the rods and the rings havebeen very imperfect', thereby greatly diminishing the efiiciency' of thearrangement.

' the rotating field vIt is 'the object of my present invention 'toimprove these re'vious structures so that the hunting may e morecompletely damped i and furtherto .utilize the rings to give greater i'idity to"thetfie1d-structures and l retainth'e d coils lace.

. The novel eaturesof my invention will be apparent from thedescriptionand drawings and willbe particularly pointed out in theclaims. j.

Figure 1 shows inuperspective a port'on'lifpf' Specification of LettersPatent.

Application' flled May 13, 1907. Serial No. 373,493.

magnets of' a dynamo--Iv electric machine embod ing' my invention;elevation of part of' one of the lfield po1eieces; Fig. 3 is an end`Fig. 2 is a partly sectiona field member of a dynamo-electric machineare mounted' any desiredmannerflpn the Spider 11. The'lamin'ae of eachpolelece lie between two end-plates'12. The coi s 13 arel here shown asbeing composed ofv edgewise- 'wound metallic ribbon. The-field coils*are retained in place and the field ole-piecesare' braced by rlngs 14which are p aced on either side of. said pole-pieces and eXtend'entirely Patented Oct. 27, 1908.-

around the rotor. These rings are l}:referably ;'made of brass or othergood conducting material and are a proXimate-ly L-shaped in'cross-section. Fanges 15 from these rings, engage notches 16 in theplates 12.

One or more rods 17, also=of brass'or other versely through each of thepole-pieces and through the rings 14.l -Asplit sleeve 18,A'frusto-conical exteriorly, fits snugly over each end of eachrod 17electrical andmechanical-contact with the 'rings 14. Witht'hisarr'angement there is'f` practically no resistance in the joint's between the rods l 7 andfthe rings 14.

tendency to hunt is immediat'ely and effectively damped out. Manymodifications in. the arran There is therefore 'practically na...opposition to? the .fiow of strong antifhuntingcurrents :and any 'goodconducting material, extend trans-" Vings 19, wedging the sleeves firmlyinto bothv w i and into 'a corresponding opening 19 in-'the ring 14." By

.means of nuts 20 which 'engage threads on l rods passing through Sai 4.In a dynamo-electrio machine, a rotary field member having radialiyextending field poles, eols on said field poles, damper rods extendingthrough said field poles, and unitary means for eleetrieally connectingthe ends of said rods, for braoing the field poles, i

and for retainng the field eoils in place.`

5. In a dynamo-electrio machine, a rotary field member having radiate'field poles, eoils on said po1es,damper rods extending through saidpoles, and a conducting ring on eaeh side of said poles for bracing thelatter, retaining the field coils in place, and eleetrically connectingthe damper rods.

In testimony Whereof I affix my signature, :inA the presence of twowitnesses.

ALLAN B; FIELD. VVtnesseszi GEO. B. SCHLEY, FEED J. KIN'BEY

